The Effect of E-Cigarettes on the Human Heart Studied using Cardiomyocytes Generated from Induced Pluripotent Stem Cells

Although many dangerous effects of smoking e-cigarettes on lungs have come to light, limited and only qualitative efforts have been made to analyze the impact of e-cigarettes on the human heart directly. In this study, we experimentally determined e-liquid cardiotoxicity in both healthy cells and cells with long QT syndrome by treating healthy and diseased human cardiomyocytes with e-liquids with varying nicotine concentrations. These cardiomyocytes were generated from human induced pluripotent stem cells. The cardiomyocytes were divided into 5 groups, a control group and 4 test groups, each treated with e-liquid containing varying amounts of nicotine between 0% and 70%. The cells biological indicators such as heart rate, pulse pressure, essential protein concentration, and metabolic activity, were measured and characterized using three different functional assays: contractility, Western blot, and viability, and tracked over 4 days. The results demonstrated that acute exposure to e-liquid led to tachycardia, hypertension, decreased protein levels, and cell death. The rate of cardiotoxicity increases with higher nicotine concentrations. The basal fluid also showed non-negligible toxicity. Under identical conditions, the functionality of the diseased heart cells declined at a faster rate compared to healthy cells. Overall, this work establishes the harmful physiological effects of e-cigarettes on the human heart quantitatively.